The invention relates to the technical field of industrial food processing systems, and specifically to a closed loop system for making ice confections of the kind also referred to as "popsicles", having a holding stick embedded therein.
As is known, industrial plant systems for making ice confections, such as ice creams and ice candies molded around a holding stick, fall within two general types, namely: circular systems and linear systems.
In circular type systems, the dies or molds wherein the ice confections are formed are associated with large rigid plates in the shape of annular segments. Each plate carries several rows of dies, depending bucket-like from the bottom side of the plate, and all the plates are set close against one another to form an unbroken flat annulus lying on a horizontal plane and being advanced stepwise. Arranged below the annulus are means of chilling the dies, and work stations are provided all around the outer rim of the annulus, such as filling stations whereat the dies are first filled with appropriate liquids or custards and then, after the latter have been chilled to a somewhat harder consistency, fed in with the holding sticks, and shake-out stations whereat, on completion of the die chilling step and the liquids or custards setting to a solid hard consistency, the ice confections are taken out of the dies.
A significant drawback of such systems stems from their overall size. The area inside the annulus formed by the dies cannot be utilized because it lies practically out of reach, and all the work stations are to be located outwards from the broad outer rim of the annulus.
On the other hand, virtually all of the plate travel path can thus be utilized to chill the dies and for the die filling and shake-out steps, and the large-size plates simplify the system layout as well as the assembly and maintenance operations. As a result, such systems afford a high degree of efficiency and high production rates.
Linear systems are more compact. The dies travel along a path defined by two superimposed linear sections connected to each other by two semicircular end sections, and the work stations may be located at the system periphery as desired.
These system dies are laid in rows over a large number of battens or strips having a much reduced length along their direction of movement, thereby forming together a flexible band which remains unbroken even while travelling along the curved sections.
Despite such benefits, linear systems have not supplanted the circular ones mainly on account of the serious drawback that only the upper straight section can be substantially utilized therein for all the ice confection making operations of die filling, chilling, and shaking out. It follows that the useful chilling section is made shorter, thus lowering the production rate.
Despite their above-mentioned drawbacks, both circular and linear type systems are widely used, also because of the cited travel path and shape combinations of the plates or strips avoiding problems from cold losses by virtue of the various plates or sticks being set close together in an unbroken configuration, whilst the dies, which must be properly positioned and arranged at all times, may be driven in a simple and accurate fashion to enable operation of the filling and shake-out stations acting on the individual dies.
With such systems, the dies can be driven and positioned accurately because the plates or strips are held close together and form continuous snugly fitted bands which are free from oscillations and can be easily driven and trained.
Some attempts at devising systems which could obviate the cited drawbacks confirm that such drawbacks have a marked influence in the specific field of icecream makers and that they are quite difficult to remedy. Reference may be had in this respect to U.S. Pat. No. 4,352,830, which teaches the use of thin strips, each with two rows of dies, guided along two coplanar, side-by-side linear path sections. Switching from one section to the other takes place by a sideways movement of the strips being performed by changing the strip leading side in the direction of advance and shifting the strips to a direction at right angles to their former direction of movement.
Only one strip can be switched from one linear section to the other. Furthermore, in the two linear sections the strips have oppositely set leading sides in the direction of advance.
With this system, switching the strips from one linear section to the other is a critical and complex step, switching of the strips being an operation to be carried out on the fly not to slow the strip motion, given that only one strip is allowed to perform a change of a lane at a time. This condition forbids the use of large size plates, each carrying several dies. Further, the members for controlling the movement of the strips along one linear section are quite separate from those for the other section.
It should be also considered that all the end sections of both linear sections cannot be used with this system for any of the cited filling, chilling, and shake-out steps, the end sections being reserved for said strip change of lane.